ChainFETCH MCP Server

Instructions

Implementation Reference

• index.js:368-381 (registration)

  Registration of the 'get_block_info' tool in the ListTools response, including name, description, and input schema.

  {
    name: 'get_block_info',
    description: 'Get detailed information about a specific block',
    inputSchema: {
      type: 'object',
      properties: {
        block: {
          type: 'string',
          description: 'The block number to get info for',
        },
      },
      required: ['block'],
    },
  },

• index.js:371-380 (schema)

  Input schema definition for the 'get_block_info' tool, specifying the required 'block' parameter as a string.

  inputSchema: {
    type: 'object',
    properties: {
      block: {
        type: 'string',
        description: 'The block number to get info for',
      },
    },
    required: ['block'],
  },

• index.js:733-735 (handler)

  Handler implementation for 'get_block_info' tool. Extracts the block number from arguments and forwards the request to the ChainFETCH API endpoint /api/v1/ethereum/blocks/{block}.

  case 'get_block_info':
    const { block } = args;
    return await this.makeRequest(`/api/v1/ethereum/blocks/${block}`, 'GET', {}, null, token);

• index.js:634-682 (helper)

  Helper method 'makeRequest' used by the handler to perform authenticated HTTP requests to the ChainFETCH API.

  async makeRequest(endpoint, method = 'GET', params = {}, body = null, token = null) {
    const chainfetchToken = token || process.env.CHAINFETCH_API_TOKEN;
    
    if (!chainfetchToken) {
      throw new McpError(
        ErrorCode.InvalidRequest,
        'CHAINFETCH_API_TOKEN is required'
      );
    }
  
    const url = new URL(`${API_BASE_URL}${endpoint}`);
    
    // Add query parameters for GET requests
    if (method === 'GET' && Object.keys(params).length > 0) {
      Object.entries(params).forEach(([key, value]) => {
        if (value !== undefined && value !== null) {
          if (Array.isArray(value)) {
            value.forEach(v => url.searchParams.append(`${key}[]`, v));
          } else {
            url.searchParams.append(key, value.toString());
          }
        }
      });
    }
  
    const fetchOptions = {
      method,
      headers: {
        'Authorization': `Bearer ${chainfetchToken}`,
        'Content-Type': 'application/json',
      },
    };
  
    if (body && method !== 'GET') {
      fetchOptions.body = JSON.stringify(body);
    }
  
    const response = await fetch(url.toString(), fetchOptions);
    
    if (!response.ok) {
      const errorText = await response.text();
      throw new McpError(
        ErrorCode.InternalError,
        `API request failed: ${response.status} ${response.statusText} - ${errorText}`
      );
    }
  
    return await response.json();
  }